Electron-Transfer Kinetics in Polymetallic Carbon-Rich Ruthenium(II) Bis(σ-arylacetylides) Wires Connected to Gold

Molecular wires consisting of Ru-II bis(sigma-arylacetylide) organometallics functionalized with different anchoring groups (thiol, isocyanide) connected with different bridges [empty set, -CH2-, -O-(CH2)(6)-] were self-assembled onto gold surfaces. The materials were characterized through wettability, ellipsometric, infrared absorption reflection, and electrochemical measurements. The dynamics of the electron transfers within the monolayers were examined with high-speed voltammetry. Similar fast electron-transfer dynamics (10(4)s(-1)) associated with discrete oxidation events (up to four distinct oxidation states) at remarkably low potentials (0.7V vs. SCE) were observed for all complexes. Neither the extension of the molecular wires, nor the variation in the anchoring/bridging units, led to the decrease in electron-transfer kinetics. These results highlight the potential of Ru-II bis(sigma-arylacetylide) complexes as a charge-storage medium for processing information in multibit devices with low power consumption.